The San Diego County Health and Human Service Agency is reminding parents that 11- and 12-year-old children must be immunized against pertussis, also known as whooping cough, before entering seventh grade.

A new law that went into effect last year requires a whooping cough booster shot, or Tdap, before middle and high school students can re-enter school.

This year, all students going into seventh grade will be required to show proof of a pertussis booster shot or they will not be allowed in school. The law includes new and transfer students in public and private schools.

Students who have already received the vaccine only need to supply proof to the school.

Parents can obtain the vaccines, including the Tdap booster shot, for themselves and their children through their primary care physicians. Local retail pharmacies offer vaccinations for a fee, and anyone who is not covered by a medical insurance plan can get the shot from a County Public Health Center at little or no cost.

For more about whooping cough and ongoing vaccination clinics, call the HHSA Immunization Branch at 866-358-2966, or visit www.sdiz.org.